<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div.content[title]{
            font-weight: bold;
        }
        input[name~=user]{
            /*background-color: red;*/
            /*border: red;*/
            width: 800px;
        }
    </style>
</head>
<body>
    <div class="content" title="内容"></div>
    <div class="content"></div>
    <form action="">
        <input type="text" name="username">
        <input type="text" name="usersex">
        <input type="text" name="userage">
    </form>
</body>
</html>